1. Field of the Invention
The present invention relates to a plasma display apparatus and driving method of the same, in particular, to a drive waveform of the plasma display apparatus applied to a scan electrode and a sustain electrode in order to leave a large amount of wall charges after a sustain period in the previous subfield is terminated.
2. Description of the Background Art
The plasma display panel is an image display apparatus where a discharge cell is formed between a rear substrate in which a barrier rib is formed and a front substrate which is faced with the rear substrate, implementing an image by stimulating a fluorescent substance with vacuum ultraviolet ray which is generated during the inactive gas in each discharge cell is discharged with a high frequency voltage.
Conventionally, the plasma display panel implements a predetermined image by using the visible light such as Red R, Green G, Blue B generated when Vacuum Ultra-Violet VUV ray radiated from plasma obtained through gas discharge excites the fluorescent substance.
The plasma display apparatus implements an image as an opposite discharge or a surface discharge is generated in the discharge cell by the driving voltage which is applied to the scan electrode, the sustain electrode and the address electrode. For this, the scan electrode, the sustain electrode and the address electrode are connected to a scan driver, a sustain driver and an address driver respectively.
Further, the scan driver, the sustain driver and the address driver divide one frame into one or more subfields. Each subfield comprises a reset period, address period and sustain period, while a set up signal and a set-down signal for initializing the discharge cell are applied in the reset period, the discharge cell is selected in the address period due to the voltage difference between the scan pulse applied to the scan electrode and the data pulse applied to the address electrode, the sustain pulse is alternately applied in the sustain period to the scan electrode and the sustain electrode so that a discharge may be maintained in the selected discharge cell.
Further, conventionally, an erase pulse which generates erase discharge during erase period for the wall charge erase is applied between the sustain period and the reset period, that is, after the sustain period is terminated.
That is, in the erase period, the low potential voltage level is maintained in the scan electrode and the address electrode, while the erase pulse gradually increasing from the low potential voltage level to the positive polarity voltage level is applied to the sustain electrode to generate the erase discharge. Accordingly the wall charge of on cell is erased to be nearly 0 V.
For this reason, in the conventional driving method of the plasma display apparatus, a set up signal rising to a high voltage level had to be applied in order to perform a set up discharge during reset period of the subfield after the erase period. Therefore, there is a problem in that dark discharge is strongly generated to increase the luminous output, while the contrast of image displayed through the panel is degraded.
Further, if the erase discharge unsteadily occurs during the erase period, the wall charge distribution inside of the cell becomes uneven before the initiation of the next reset period, such that a misdischarge occurs. Therefore, there is a problem in that a drive margin becomes narrow.